Vibrator



Sept. 2, 1969 H. PICK 3,464,674

VIBRATOR Filed Jan. 19, 1968 INI/E P Helmu/ PIC/f United States PatentUS. Cl. 259--72 6 Claims ABSTRACT OF THE DISCLOSURE A vibrator has anannular material receptacle that is resiliently supported in asubstantially horizontal position and rotated about a substantiallyvertical axis, and an out-of-balance shaft that extends through thereceptacle.

This invention relates generally to material handling devices and moreparticularly to an improved vibrator of the type known sometimes as avibratory mill.

Prior art devices in the field to which this invention is directed werecomprised of annular work receptacles having semi-circular orrectangular transverse cross sections. The receptacles were vibrated byone or more out of phase, unbalanced masses that were mounted on a driveshaft. The unbalanced masses were secured to the shaft at some distanceto the plane of the horizontal center of gravity of the receptacle whichwas concentric with the axis of the shaft. Examples of this general typeof prior art devices are U.S. Patents No. 2,882,024 and 3,100,088.

In this first form of the prior art, the material in the receptacle wasdriven along a path conforming to the shape of the receptacle and, inaddition, was moved transversely to the annular path. Thus the materialactually moved along a helical path that resulted from the combinedmovements described immediately above. The relative movements of thearticles in the receptacle, in turn, resulted in the grinding orpolishing thereof.

Another form of the prior art is described in German Patent No. 937,055and French Patents Nos. 1,264,058 and 1,544,181. These structures used acombination of turning and swinging motions to agitate the receptaclegrinding or polishing means, and where necessary, a fluid was used inthe receptacle together with the work pieces.

One shortcoming of the prior art devices is that the receptacles couldbe moved at only a very limited rotational speed. The articles onlypartly filled the receptacle and formed a slanted surface layer. As thereceptacle rotated, the articles near the top fell to the bottom and inthis manner the material was circulated. Only a segment of thetransverse area of the receptacle was utilized, however, and thusrequired a considerable length of time to complete a Work cycle.

Accordingly it is an object of this invention to provide an improvedvibrator for vibrating articles therein.

It is another object of this invention to provide an improved articlevibrating device having a resiliently supported, rotary driven articlereceptacle and means to unbalance the receptacle as it rotates.

A further object of this invention is to provide a more compactarrangement of the above mentioned vibrating device.

A particular object of this invention is to provide means for impartinga combination of rotary and swinging motions to the articles containedin a vibrating device while at the same time altering the angularvelocity of the articles.

By way of contrast to the prior art, the present invention broadlyprovides for an annular work piece receptacle that has a substantiallytoroidal shape. In particular in one of the embodiments of the instantinvention, the two lower quadrants and at least a portion of one of theupper quadrants of the receptacle are curved; the partially curved upperquadrant is provided with an upwardly extending outer wall section; andan inner wall section extends upwardly from the opposite, lower quadrantto define an entrance throat into the receptacle.

The receptacle is supported from beneath on springs that extend towardsthe rotational axis of the receptacle. A hollow support member providesthe mounting means for the lower ends of the springs, the upper ends ofwhich are secured to the lower surface of the receptacle. Drive meansare provided for rotating the support member about the axis of thereceptacle. A motor driven shaft, having out-of-balance masses securedthereto, extends through the hollow support means and is rotatablyjournalled in the receptacle. Thus, when both motors are energized, thereceptacle will rotate along an irregular path.

As the receptacle and the support member are driven, the articles in thereceptacle are thrown outwardly due to centrifugal force. As thearticles have a gravitational force of their own, however, which forceis directed downwardly, the resultant force on the articles is directeddownwardly and outwardly. The resultant force thus pro duced is somewhatsmaller than the acceleration imparted to the articles due to theswiging motion of the receptacle and the net effect is periodically toalter the magnitude of the resultant force.

The magnitude of the centrifugal force depends on the rotational speedof the articles in the receptacle. The swinging motion of the receptaclewhich is added to the rotational motion of the receptacle causes avariation in the centrifugal force thus creating a loosening or aeratingeffect on the articles therein. The swinging motion occurs on a closed,curved path which coincides at times with the rotational movement of thearticles and is, at other times, opposite thereto.

Because of the combined rotating and swinging motions that result from aresilient, rotary drive system, the movement of the articles within thereceptacle occurs with a periodically changing angular velocity. Duringthe acceleration and retardation of the articles there also occurs amultiplication of the movement of the articles with respect to eachother and particularly a squeezing between, or compaction of, the partswhich constantly changes in magnitude. The squeezing movement betweenthe parts causes still additional movement of the articles. It willtherefore be apparent that the combination of all of the articlemovements will greatly shorten the work cycle required to achieve therequired finish in the articles.

Another feature of the construction of the receptacle is that theconcave outer wall prevents the articles from being hurled out as thereceptacle rotates. The curved cross sectional shape also serves toguide the articles into a revolving movement as a result of the swingingmovement of the receptacle. Further, since the curved side walls act toretain the articles during rotation, the upper side of the receptaclemay be left open, thus preventing the building of excessive internalpressures and facilitating the loading and unloading of the receptacle.

Turning now to the drive means for the receptacle, it will be seen thatthe resilient support therefor permits the addition or summation of therotational and swinging movements of the receptacle. The resilientsupport is provided by a plurality of springs which are set at an angleto the rotational axis of the work support and thereby contributes toboth the rotating and swinging action of the receptacle which isvibrated by means independent of the drive means for the support member.

A feature of this invention is that the entire device may be made verycompactly by concentrically surrounding the unbalanced shaft with theannular work piece receptacle. Another constructional feature of theinvention is the provision of two out-of-balance masses that areout-of-phase with each other. The lower mass is placed below thehorizontal plane of the center of gravity of the work piece receptacleand the upper mass is placed no lower than the horizontal plane of thecenter of gravity. The axes of the angularly positioned support springsintersect at a point that is no lower than the horizontal plane of thegravity and substantially coincidental with the rotational axis of theannular work piece receptacle.

The aforementioned construction transmits the rotary and swingingmovement of the receptacle to the contents therein and the articlesthemselves move with a rotary movement in the cross section of theannular receptacle and a curvilinear movement along the annularreceptacle. These two movements occur concurrently and in combinationwith the periodic change in the angular velocity of the articles in thereceptacle.

The foregoing and other features, objects and advantages of theinvention will, in part, be :pointed out with particularity and will, inpart, become obvious from the following, more detailed description ofthe invention, taken in conjunction with the accompanying drawing whichforms an integral part thereof.

Referring now to the drawing, the single view of which is a sectionalview taken along the longitudinal, rotational axis of the device, thereis shown an annular work piece receptacle 1 that has a wall 2 whichincludes a concave outer wall, the largest diameter of which isdesignated as the horizontal plane x-x. Straight wall sections extendupwardly from the receptacle wall 2 to define a throat therebetween.

The receptacle 1 is supported by a plurality of springs 3 that are in aslanted position so that the spring axes intersect substantially at orabove the horizontal plane x-x of the center of gravity. The point ofintersection is substantially on the axis yy of the annular work piecereceptacle 1 at a location determined by the quantity of material in thereceptacle.

The springs 3 are carried by abutments on a hollow support member 6 thatis rotatably journalled about the axis y-y by means of bearings 4 and 5.The support member 6 is driven by a motor 7. Suitable means such as thepulley and belt system illustrated, couple the motor 7 to the supportmember 6. Thus the drive torque of the motor 7 is transmitted to thework piece receptacle 1 through the support member 6 and the springs 3,so that the receptacle 1 may be resiliently rotated.

An out-of-balance shaft is journalled concentrically within the hollowsupport member 1. The shaft 10 is driven through a flexible coupling 9by a motor 8. The shaft 10 is rotatably journalled in a downwardlyextending portion 13 of the receptacle 1 by means of bearings 11 and 12.

The out-of-balance shaft 10 has out-of-balance masses 14 and 15 securedthereto. The out-of-balance masses are axially spaced from each other onthe shaft 10 and angularly out-of-phase with each other. The mass 14 islocated at a distance below the horizontal plane of the center ofgravity which coincides with the x-x plane. The mass 14 may also bepositioned as high as the x--x plane. The mass 15, on the other hand, islocated substantially at the x-x center of gravity plane or may even bepositioned higher than that.

When the out-of-balance shaft 10 is driven by the motor 8, the workpiece receptacle 1 is given a sawtooth oscillation in a well knownmanner. The rotation of the axis of the out-of-balance shaft '10 forcesall points lying thereon to generate a cylindrical path obliquely aboutthe surface of a theoretical hyperboloid. The surfaces follow a circularpath in a region free from surfaces bordering the annular space andterminate along the broken line 16.

The contents of the work piece receptacle 1 thereby carry out a rotarymovement in the annular cross section in the direction of the arrowshown in the drawing.

The contents of the receptacle also carry out a forward movement in theannular space. By a combination of these two movements, the contents ofthe receptacle 1 traverse a screw thread course.

'Due to the varying movements of the articles in the work piecereceptacle, in combination with the sawtooth oscillation of thereceptacle, the parts in the receptacle move relative to each other. Theaccelerating and decelerating forces of the swinging motion also causean intermixing of the articles in the receptacle 1.

When the receptacle 1 is rotated by the motor 7 about the axis y-y,simultaneously with the rotation of the shaft 10 and the unbalancedmasses 14 and 15, then a centrifugal force F is produced on the articlesin the receptacle. A gravitational force also acts on the articleswhich, in combination with the centrifugal force produces a resultantforce R. The revolutions per minute of the work piece receptacle areproportional to the diameter of the annular receptacle 1 so that theresultant force R is smaller than the accelerating force produced by theswinging motion of the receptacle that periodically falls in a directionopposite to the direction of the resultant force R.

The centrifugal force F efiects an increased compression of the articlesin the receptacle 1 and therefore an increased mutual influence of thearticles on each other. A loosening effect is also maintained by therespective relative movements of the articles, however, due to thelimitation .of the extent of the resulting force R.

The material in the receptacle acquires a volumetric form which proceedsin the area free from the receptacle wall along the line 17. Thisresults from the simultaneous swinging and rotary movements of thereceptacle 1 and the maintenance of the screw thread course in thecircular direction of the direction of the annular receptacle 1.

A portion of the curved swinging motion is in the direction of therotation of the receptacle, while the remaining portion of each cycle ofcurved swinging motion is opposite to the direction of receptaclerotation. As the swinging motion of the receptacle 1 occurs on closed,curved paths, there results from these opposed motions a receptaclerotation with periodically varying angular velocity. This change ofangular direction of the receptacle further increases the intensiverelative movements of the articles in the receptacle.

Que to the intensive relative movements and the periodic varying of thecompression of the articles reresulting from increased centrifugalforces, the articles are subjected to an interaction among each other.Thus the work processes of grinding, mixing, kneading or surface workingof the articles is possible in short work periods.

I wish it to be understood that I do not desire to be lmited to theexact details of construction shown and described, for obviousmodifications will occur to a person skilled in the art.

Having thus described the invention, what I claim as pew and desire tobe secured by Letters Patent is as folows:

1. A vibrator, for use in vibrating material, compris- (a) an annularreceptacle adapted to receive and to hold material to he vibrated;

(b) support means rotatably and resiliently driving and supporting saidreceptacle substantially horizontially; and

(c) a rotatable upright shaft having means applying an unbalanced forceto said receptacle during the rotation thereof in such a manner that theresultant force applied to the material by the combined centrifugal andgravitational forces due to the rotation of the receptacle is smallerthan the accelerating force of the swinging movement which periodicallyfalls in the direction opposite to that of said resultant force.

2. A vibrator in accordance with claim 1, wherein said receptacle has,in cross section, an arcuate outer wall, the largest diameter of whichis substantially in the horizontal plane of the center of gravity ofsaid receptacle.

3. A vibrator in accordance with claim 1, wherein said support means isa hollow, rotatable member having a plurality of springs extendingupwardly therefrom and into engagement with the underside of saidreceptacle, the axes of said springs intersecting substantiallycoincidentally with the rotational axis of said receptacle and at apoint at least as high as the horizontal plane of the center of gravity.

4. A vibrator in accordance with claim 1, wherein said means applying anunbalanced force is comprised of at least two masses secured to saidupright shaft, said masses being axially spaced on said shaft andangularly ofi-set from each other.

UNITED STATES PATENTS 1,448,446 3/1923 Hulbert 259-72 2,882,024 4/1959Behrens et at 259-72 X I 3,268,177 8/1966 McKibben 241-175 3,400,4959/1968 Balz 241-175 X 3,422,577 1/1969 McKibben 259-72 X WILLIAM I.PRICE, Primary Examiner US. Cl. X.R.

